我们可以创建一个Application Load Balancer，在ECS服务中为每个任务定义一个任务定义，并将其与负载均衡器关联。我们还需要为每个任务定义设置容器端口和协议。

以下是一个示例CloudFormation模板，该模板创建了一个ECS服务、一个Application Load Balancer和关联的任务定义。

Resources:
  EcsCluster:
    Type: AWS::ECS::Cluster

  EcsTaskRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
        - Effect: Allow
          Principal:
            Service:
            - ecs-tasks.amazonaws.com
          Action:
          - sts:AssumeRole
      ManagedPolicyArns:
      - arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy

  EcsTaskDefinition:
    Type: AWS::ECS::TaskDefinition
    Properties:
      TaskRoleArn: !GetAtt EcsTaskRole.Arn
      Family: my-task
      ContainerDefinitions:
        - Name: my-container
          Image: my-image
          Cpu: 256
          Memory: 512
          PortMappings:
            - ContainerPort: 80
              Protocol: tcp

  EcsService:
    Type: AWS::ECS::Service
    Properties:
      Cluster: !Ref EcsCluster
      TaskDefinition: !Ref EcsTaskDefinition
      LaunchType: FARGATE
      DesiredCount: 2
      NetworkConfiguration:
        AwsvpcConfiguration:
          Subnets:
            - !Ref Subnet1
            - !Ref Subnet2
          SecurityGroups:
            - !Ref SecurityGroup
      LoadBalancers:
        - ContainerName: my-container
          ContainerPort: 80
          TargetGroupArn: !Ref TargetGroup

  LoadBalancer:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Scheme: internet-facing
      Type: application
      LoadBalancerAttributes:
        - Key: idle_timeout.timeout_seconds
          Value: '60'
      Subnets:
        - !Ref Subnet1
        - !Ref Subnet2
      SecurityGroups:
        - !Ref SecurityGroup

  TargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      TargetType: ip
      Port: 80
      Protocol: HTTP
      VpcId: !Ref Vpc
      Tags:
        - Key: